Two conditioners can share the same emulsifier, the same oil phase and the same preservative system, and still behave nothing alike - because one carries cetyl alcohol and the other stearyl. In straight-chain fatty alcohols, the entire design space is the carbon count: every two carbons added to the chain push the melting point up by roughly seven degrees, walking you from a freely flowing oil at -15.5 degrees C to a hard wax that melts at 70. That single variable decides whether the product pours, pumps, stands in a jar, or leaves a matte film - and it should decide what you write on the purchase order.
The melting-point ladder: one variable, eight textures
| INCI (chain) | CAS | Melting point | State at 25 degrees C | What it delivers | Typical use level |
|---|---|---|---|---|---|
| Capryl Alcohol (C8) | 111-87-5 | About -15.5 degrees C | Clear liquid | Low-viscosity oil-phase carrier and spreading emollient | 0.5-3% |
| Capric Alcohol (C10) | 112-30-1 | 6.9 degrees C | Liquid | Light spreading emollient, co-solvent for oil-soluble actives | 0.5-3% |
| Undecyl Alcohol (C11) | 112-42-5 | About 16-19 degrees C | Borderline liquid | Fluid emollient with a mild citrus-fatty masking note | 0.5-2% |
| Lauryl Alcohol (C12) | 112-53-8 | 23.9 degrees C | Semi-solid to solid | Mostly a surfactant feedstock (lauryl sulfate and ether sulfate route) | 0.5-2% direct |
| Myristyl Alcohol (C14) | 112-72-1 | About 39 degrees C | Waxy solid | Light, silky body in lotions | 1-3% |
| Cetyl Alcohol (C16) | 36653-82-4 | 49.3 degrees C | Waxy solid | Slip, cushion, gel-phase viscosity | 1-6% |
| Stearyl Alcohol (C18) | 112-92-5 | 57-58 degrees C | Hard flakes | Drier, firmer body; more opacity; stable viscosity | 1-4% |
| Behenyl Alcohol (C22) | 661-19-8 | About 70 degrees C | Hard wax | Matte structure, hot-oil thickening; pharma grade is docosanol | 0.5-2% |
Two commercial cuts fill the gaps: C8-10 Fatty Alcohol (CAS 85566-12-7), the standard feedstock for ethoxylates and phosphate esters, and C12-14 Fatty Alcohol (CAS 80206-82-2), the workhorse behind lauryl and laureth sulfates. Unlike the ethoxylated families - where one CAS number covers the entire EO ladder - every straight-chain alcohol has its own CAS, which makes sourcing cleaner but also means a "cetyl alcohol" quotation must still be verified as a genuine C16 cut, not a blended fraction, by GC assay.
Where the liquid-to-solid crossover sits - and why the warehouse cares
The crossover between liquid and solid sits almost exactly at C12. 1-Decanol flows at room temperature; 1-dodecanol melts at 23.9 degrees C, which means a drum that is pourable in a 30-degree C warehouse in August is a solid block in a 15-degree C warehouse in January. That is a handling and pumping problem before it is a formulation problem, and it is worth settling with your supplier up front: drum versus flake form, heated unloading, and whether the quotation is on a summer or a winter logistics profile. C11 is the odd one out - at 16 to 19 degrees C it stays liquid across most climate-controlled rooms but will cloud or solidify in cold-chain storage, so cold-season shipments need the same caution as C12.
For buyers, this crossover is also the cleanest acceptance test in the whole family: a melting or congealing range on the certificate of analysis is a direct read of whether you received the chain length you paid for. A C12 lot that congeals well above 24 degrees C is carrying heavier cuts; a "cetyl" lot that melts below 47 degrees C is not a pure C16.
C16 versus C18 in emulsions: not interchangeable
- Cetyl alcohol is the more polar of the two and holds more water in the lamellar gel network, so it builds a higher gel phase and faster viscosity - but that viscosity can drift upward over storage time.
- Stearyl alcohol crystallizes in a different, less polar structure; it gives less initial viscosity but holds it steadier on the shelf, and it makes the finished emulsion whiter and more opaque.
- Mixing the two chain lengths - the classic cetearyl approach at ratios like 30:70 or 50:50 cetyl-to-stearyl - produces a broader crystal distribution and a more robust lamellar gel network that tolerates wider temperature swings than either single chain.
- Process control matters as much as chemistry: melt the oil phase at 70-75 degrees C so every crystal dissolves, then keep agitation running through the 50-40 degrees C window on the way down. Fast cooling in that zone gives small crystals and a smooth feel; slow cooling lets large crystals grow and ends in graininess that no homogenizer fixes after the fact.
Practical windows from supplier and formulator literature: face creams run cetyl or cetearyl at 2-5%, body lotions at 1-3%, and cationic hair conditioners built on BTMS-type emulsifiers run 3-10% total fatty alcohol, where stearyl provides the salon-thick backbone.
Anhydrous balms and sticks: crystal modifiers, not wax
In a balm, fatty alcohols do not gel the oils - they modify the crystal network the waxes form. Two to three percent of cetyl takes the drag out of a hard-waxed lip balm and stops a body balm weeping oil in a warm room; stearyl and behenyl add drier, firmer body. The ceiling is real: above roughly 6% the product turns waxy and dull, so if a balm brief is not landing, the fix is usually a shorter-chain partner or a different wax ratio - not more fatty alcohol.
The C22 outlier: behenyl alcohol has a pharmaceutical twin
Behenyl alcohol is chemically identical to docosanol, approved by the FDA in July 2000 as an over-the-counter topical antiviral (10% cream, sold as Abreva) for shortening cold-sore healing. Pharmaceutical demand for docosanol coexists with the cosmetic market, which matters in two directions: pharma-grade material with full ICH documentation commands a premium, and cosmetic-grade behenyl for a marketed product can be positioned with the same molecule's OTC history as a safety talking point. In texture terms, C22 is the driest and most matte of the family and thickens hot oil efficiently, which is why it shows up in pomades, hot-pour sticks and matte-finish creams.
What belongs on the purchase order
- Chain identity by CAS number, plus a GC chromatogram confirming the cut is what the INCI claims - a single CAS does not stop a supplier from shipping a blended fraction.
- Melting (or congealing) range as an acceptance criterion, interpreted as a band: cetyl 49-52, stearyl 57-60, behenyl 65-73 degrees C across commercial grades.
- Hydroxyl value within a tight range - it is the cleanest single indicator of chain-length purity.
- Acid value (low), carbonyl value (low) and iodine value (very low for saturated grades) - the trio that predicts color and odor stability on storage.
- Origin and compliance: coconut, palm or rapeseed feedstock for vegetable grades, with RSPO documentation when palm-derived; cosmetic grades against the relevant pharmacopoeial monographs where claims demand it.
Quick selection
- Need a pourable, light oil-phase carrier: C8 or C10.
- Need slip and fast viscosity build in a lotion: cetyl at 1-6%.
- Need a firmer, whiter, shelf-stable viscosity: stearyl, or a 50:50 cetearyl blend.
- Need matte, dry structure in sticks and hot-pour products: behenyl at 0.5-2%.
- Need a surfactant feedstock, not a texture agent: C8-10 for ethoxylates, C12-14 for lauryl sulfates.
Shanghai Better Chemical supplies the full straight-chain ladder - Capryl Alcohol (C8, CAS 111-87-5), Capric Alcohol (C10, CAS 112-30-1), Undecyl Alcohol (C11, CAS 112-42-5), Lauryl Alcohol (C12, CAS 112-53-8), Myristyl Alcohol (C14, CAS 112-72-1), Cetyl Alcohol (C16, CAS 36653-82-4), Stearyl Alcohol (C18, CAS 112-92-5), Behenyl Alcohol (C22, CAS 661-19-8), plus the C8-10 (CAS 85566-12-7) and C12-14 (CAS 80206-82-2) cuts - with COAs covering melting range, hydroxyl value and iodine value, and drum or flake packing matched to your plant's unloading setup. Tell us the texture you are targeting and we will quote the chain that gets you there.